Processing an image of an eye

An image of an eye is first captured and stored at step S1, as a 256 grey level image or as a colour image, and is then evaluated along a plurality of horizontal, vertical and diagonal lines (fig. 9) at step S2 to determine thresholds between the values of pixels representing different parts of the eye. The thresholds are used to determine the boundary between the pupil and the iris along various lines at step 53, and these are then used to determine the centre of the eye. The boundary between the iris and the sclera is determined at step 54. Once the location of the iris has been found, the image is further processed using concentric sections of the iris (fig 12) to extract a biometric code using a linearisation procedure at step S5 followed by a wavelet transformation at step S6 to produce a linear signal of predetermined length. Finally, a biometric code is output by the processor at step S7. This method is less computationally intensive than conventional methods allowing it to be used on PDAs and mobile phones.